The authors differ on the origin of this surname. F. Miranda notes that it could derive from several Italian place names called Rosano, among them a district of the municipality of Cabella Ligure, in the province of Alessandria, and a district of the municipality of Rignano sull'Arno, in the province of Florence. Miranda also points out that it could come from the medieval name Rosanus, of Sanskrit-Persian origin, with the meaning of "shining, splendid, small luminous star," and mentions that E. De Felice considers it simply a variant of Rosa.

P. Durante, on the other hand, proposes a Greek origin, linking it to the root rhothos, with the sense of "noise."

The surname presents its areas of greatest presence in Sicily, with a concentration in the provinces of Catania, Trapani, Syracuse, Palermo and Enna. Miranda also records a presence of lesser intensity in Piedmont, Campania, Calabria, Lombardy, Basilicata, Tuscany, Emilia-Romagna, Lazio, Apulia, Liguria and Veneto.